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