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