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