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