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