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)(11,20)(12,17)(13,27)(14,26)(15,19)(16,23)(18,28)(21,34)(22,35)(24,37)(25,36)(29,30)(31,39)(32,38)(33,40)(9,11,21,38,14,22,13,23,15,24,28,39,12,25,29,40)(10,16,30,35,17,32,18,20,19,33,27,36,26,31,34,37)(2,4)(9,10)(11,16)(12,26)(13,18)(14,17)(15,19)(20,23)(21,30)(22,32)(24,33)(25,31)(27,28)(29,34)(35,38)(36,39)(37,40) involution — undirected(5,7,8,6)(9,12,15,14)(10,17,19,26)(11,22,24,25)(13,21,29,28)(16,31,33,32)(18,27,34,30)(20,35,37,36)(23,39,40,38)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.