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