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