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