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