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