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