One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,5)(6,8)(13,21)(18,22)(19,24)(20,23)(25,26,30,34)(27,33,29,31)(28,32,36,39)(35,40,37,38)(2,4)(6,7)(9,10)(11,16)(12,17)(13,18)(14,15)(19,23)(20,24)(21,22)(25,27,30,29)(26,31,34,33)(28,35,36,37)(32,38,39,40)(1,3)(2,6)(4,7)(5,8)(10,15)(12,16)(18,22)(20,23)(28,36)(32,39)(35,37)(38,40) involution — undirected(1,4,5,2)(3,7,8,6)(9,11,14,17)(10,16,15,12)(13,19,21,24)(18,23,22,20)(25,26)(27,31)(28,32)(29,33)(30,34)(35,38)(36,39)(37,40)(9,12,14,16)(10,17,15,11)(13,20,21,23)(18,24,22,19)(25,28)(26,32)(27,35)(29,37)(30,36)(31,38)(33,40)(34,39)(9,13)(10,18)(11,19)(12,20)(14,21)(15,22)(16,23)(17,24)(25,29,30,27)(26,33,34,31)(28,37,36,35)(32,40,39,38)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.