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