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