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