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