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