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