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