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