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