One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,8)(3,6,7,4)(9,10,15,17)(11,20,22,16)(12,18,23,13)(14,21,24,19)(28,36)(31,38)(35,40)(37,39)(1,3)(2,6)(4,8)(5,7)(9,11,15,22)(10,16,17,20)(12,21,23,19)(13,24,18,14)(25,26)(27,32)(28,31)(29,33)(30,34)(35,39)(36,38)(37,40)(1,2)(3,4)(5,8)(6,7)(10,17)(12,23)(16,20)(19,21)(25,27)(26,29)(28,35)(30,33)(31,37)(32,34)(36,40)(38,39) involution — undirected(1,4)(2,7)(3,8)(5,6)(9,12)(10,18)(11,21)(13,17)(14,16)(15,23)(19,22)(20,24)(25,28)(26,31)(27,35)(29,37)(30,36)(32,39)(33,40)(34,38) involution — undirected(1,4)(2,3)(5,6)(7,8)(9,13,15,18)(10,12,17,23)(11,14,22,24)(16,19,20,21)(25,27)(26,32)(28,35)(29,34)(30,33)(31,39)(36,40)(37,38)(1,2)(3,6)(4,7)(5,8)(9,14)(10,19)(11,13)(12,16)(15,24)(17,21)(18,22)(20,23)(25,29,30,32)(26,33,34,27)(28,37,36,39)(31,40,38,35)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.