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