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