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