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