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