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