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