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