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