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