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