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