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