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