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