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