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