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)(11,14)(12,16)(13,17)(15,18)(19,21)(20,23)(22,24)(25,26)(27,36)(28,39)(29,30)(31,33)(32,37)(34,38)(35,40)(1,2)(3,6)(4,7)(5,8)(9,11)(10,14)(12,19)(13,18)(15,17)(16,21)(20,24)(22,23)(25,27,31,37)(26,32,33,36)(28,29,38,40)(30,39,35,34)(11,18)(12,20)(14,15)(16,23)(26,33)(27,37)(29,40)(34,39) involution — undirected(9,11)(10,15)(12,19)(13,18)(14,17)(16,22)(20,24)(21,23)(25,28,31,38)(26,34,33,39)(27,29,37,40)(30,36,35,32)(1,3,5,4)(2,6,8,7)(9,12)(10,16)(11,19)(13,20)(14,21)(15,22)(17,23)(18,24)(25,29)(26,35)(27,38)(28,37)(30,33)(31,40)(32,34)(36,39)(1,4,5,3)(2,7,8,6)(9,10)(11,15)(12,16)(13,17)(14,18)(19,22)(20,23)(21,24)(25,30,31,35)(26,29,33,40)(27,34,37,39)(28,36,38,32)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.