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