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