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